In A Quiet Place, the monsters kill any human that makes noise — but the aliens don't eat them. They strike without mercy but then abandon their victims instantly. It's an action that goes against the basic predator-prey relationship. However, that very idea reveals an important truth about the alien monsters. It's one that will likely drive the franchise forward into a potential A Quiet Place 3.
The Quiet Place movies chronicle a world after alien monsters suddenly and swiftly invade Earth. As they're blind creatures that hunt by sound, all remaining survivors are forced to live in a world of silence. Lee (John Krasinski) and Evelyn Abbott (Emily Blunt) raise their children in the new normal while attempting to find a way to kill the creatures. Over the course of the two films, the family slowly begins to unveil mysteries surrounding the noise-sensitive aliens — the most important of which is that the feedback from their deaf daughter Reagan's hearing aid hurts them and exposes their vulnerabilities.
While the Abbotts' story is central to the Quiet Place horror movie series, the mystery behind the alien monsters is almost just as important. Before his death in the first movie, Lee had copious amounts of research looking into the monsters' habits and their motivations. A Quiet Place Part II reveals a little more, showing that they suddenly crashed to earth out of thin air. Should a third film happen, it'll likely focus on Evelyn and her children leading the charge in wiping out the monsters. The fact that the monsters don't kill their prey may end up being an important aspect of that process.
One of the biggest revelations in the Quiet Place franchise is just how hyper-sensitive the creatures are to noise. When the Abbott family accidentally discovers this weakness, audiences learn that the monsters have massive and totally exposed ear canals. Because of that, any noise is like torture to them — the shrill feedback of a hearing aid is nearly debilitating. So whenever one of those creatures hears a noise, they will stop at nothing to end it. That brings up the startling revelation that they don't really care about killing humans specifically. The monsters just want the origins of the noise to stop. This is evidenced multiple times throughout the movie series, as the creatures always abandon their victims after they kill them.
The Quiet Place movie series has been slowly building to a crescendo of the Abbott family killing them all. In the first movie, they learned the survival skills to exist side-by-side with the creatures. In A Quiet Place Part II, Evelyn and her children perfected the art of killing small groups of the creatures. A Quiet Place Part III will likely focus on the Abbotts figuring out a way to kill the whole species. Taking them down will involve the family exposing the creatures' weaknesses and using it to their advantage. The monsters' biggest weakness is the fact that noise cripples them to the point that they won't even kill their prey. A Quiet Place Part II has already set up the fact that it will be the key to the Abbotts defeating the creatures. In a strange twist of fate, the creatures' killer instincts will likely lead to their extinction.